1 /*
   2  * Copyright 1999-2003 Sun Microsystems, Inc.  All Rights Reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 #include "incls/_precompiled.incl"
  26 #include "incls/_assembler_linux_x86_32.cpp.incl"
  27 
  28 void MacroAssembler::int3() {
  29   call(RuntimeAddress(CAST_FROM_FN_PTR(address, os::breakpoint)));
  30 }
  31 
  32 void MacroAssembler::get_thread(Register thread) {
  33   movl(thread, rsp);
  34   shrl(thread, PAGE_SHIFT);
  35 
  36   ExternalAddress tls_base((address)ThreadLocalStorage::sp_map_addr());
  37   Address index(noreg, thread, Address::times_4);
  38   ArrayAddress tls(tls_base, index);
  39 
  40   movptr(thread, tls);
  41 }
  42 
  43 bool MacroAssembler::needs_explicit_null_check(int offset) {
  44   // Linux kernel guarantees that the first page is always unmapped. Don't
  45   // assume anything more than that.
  46   bool offset_in_first_page =   0 <= offset  &&  offset < os::vm_page_size();
  47   return !offset_in_first_page;
  48 }